From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH] hwmon: (ltc4151) Make shunt-resistor configurable Date: Sun, 24 Jul 2016 22:19:00 -0700 Message-ID: <5795A144.2020300@roeck-us.net> References: <20160724202620.GA30245@makrotopia.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160724202620.GA30245@makrotopia.org> Sender: linux-hwmon-owner@vger.kernel.org To: Daniel Golle , linux-hwmon@vger.kernel.org Cc: devicetree@vger.kernel.org, Axel Lin , =?UTF-8?Q?Per_Dal=c3=a9n?= List-Id: devicetree@vger.kernel.org On 07/24/2016 01:26 PM, Daniel Golle wrote: > Allow to specify the resistance of the attached shunt via DT by > adding the shunt-resistor property. Fall-back to the previous > default (1 mOhm) if unset. > > Signed-off-by: Daniel Golle > --- > drivers/hwmon/ltc4151.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/ltc4151.c b/drivers/hwmon/ltc4151.c > index c86a184..f856e44 100644 > --- a/drivers/hwmon/ltc4151.c > +++ b/drivers/hwmon/ltc4151.c > @@ -30,6 +30,8 @@ > > #include > #include > +#include > +#include I don't immediately see why this include file would be necessary. > #include > #include > #include > @@ -52,6 +54,7 @@ struct ltc4151_data { > struct mutex update_lock; > bool valid; > unsigned long last_updated; /* in jiffies */ > + unsigned int shunt; /* in micro ohms */ > > /* Registers */ > u8 regs[6]; > @@ -111,9 +114,9 @@ static int ltc4151_get_value(struct ltc4151_data = *data, u8 reg) > case LTC4151_SENSE_H: > /* > * 20uV resolution. Convert to current as measured with > - * an 1 mOhm sense resistor, in mA. > + * a given sense resistor, in mA. > */ > - val =3D val * 20; > + val =3D val * 20 * 1000 / data->shunt; > break; > case LTC4151_VIN_H: > /* 25 mV per increment */ > @@ -176,6 +179,7 @@ static int ltc4151_probe(struct i2c_client *clien= t, > struct device *dev =3D &client->dev; > struct ltc4151_data *data; > struct device *hwmon_dev; > + u32 shunt; > > if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) > return -ENODEV; > @@ -184,6 +188,14 @@ static int ltc4151_probe(struct i2c_client *clie= nt, > if (!data) > return -ENOMEM; > > +#ifdef CONFIG_OF #ifdef is unnecessary. Worse, it results in drivers/hwmon/ltc4151.c: In function =91ltc4151_probe=92: drivers/hwmon/ltc4151.c:182:6: warning: unused variable =91shunt=92 if CONFIG_OF is not defined. > + if (!of_property_read_u32(client->dev.of_node, "shunt-resistor", &s= hunt) > + && shunt > 0 ) checkpatch error > + data->shunt =3D shunt; shunt =3D=3D 0 is silently accepted and replaced with 1000. This is qui= te unusual. Any reason ? If not, return -EINVAL might be more appropriate for shunt= =3D=3D 0. > + else > +#endif > + data->shunt =3D 1000; /* 1 mOhm if not set */ > + > data->client =3D client; > mutex_init(&data->update_lock); > > @@ -199,10 +211,20 @@ static const struct i2c_device_id ltc4151_id[] = =3D { > }; > MODULE_DEVICE_TABLE(i2c, ltc4151_id); > > +#ifdef CONFIG_OF #ifdef is unnecessary. > +static const struct of_device_id ltc4151_match[] =3D { > + { .compatible =3D "lltc,ltc4151" }, This as well as the property need to be documented. > + {}, > +}; > +#endif > + > /* This is the driver that will be inserted */ > static struct i2c_driver ltc4151_driver =3D { > + .class =3D I2C_CLASS_HWMON, This is an unrelated change, and appears to be quite pointless, since the driver does not have a detect function. Any reason for adding it ? If so, please explain, and submit as separate patch. > .driver =3D { > .name =3D "ltc4151", > + .owner =3D THIS_MODULE, Is this now necessary again ? If so, please explain, and submit as separate patch. > + .of_match_table =3D of_match_ptr(ltc4151_match), > }, > .probe =3D ltc4151_probe, > .id_table =3D ltc4151_id, > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html